Release film stripping mechanism for photocuring 3D printer

Abstract

According to the release film stripping mechanism for the photocuring 3D printer, a hollow shaft torque motor of the release film stripping mechanism comprises a rotor, a stator and a hollow shaft, and the stator is fixed to a workbench; the lifting pipe is in threaded engagement with the hollow shaft, and the lifting pipe can only reciprocate in the vertical direction; the sleeve is fixed on the stator, the trough is engaged on the sleeve in a threaded manner, and the guide rod on the hollow shaft is slidably arranged in the guide hole of the trough wall in a penetrating manner; when the rotor rotates, the trough reciprocates between the first working position and the second working position, and the lifting pipe reciprocates between the third working position and the fourth working position. When the material groove is located at the first working position and the lifting pipe is located at the third working position, the photocuring 3D printer conducts printing; and when the material groove is located at the third working position and the lifting pipe is located at the fourth working position, the release film is separated from the product model. The moving distance and speed of the printing platform are reduced through descending of the material groove, abrasion of the ball screw and the lead screw nut is reduced, and the service life of equipment is prolonged.

Description

[0001] This application is a divisional application. The application date of the original application is December 02, 2024. The application number is 2024117456763. The name of the invention is: Light-curing 3D printer with trough sinking peeling and light-curing 3D printing method. Technical Field

[0002] The invention relates to a release film peeling mechanism for a light-curing 3D printer. Background Art

[0003] When using the pull-up light-curing 3D printing technology for printing, the photosensitive material between the printing platform and the release film is cured under the irradiation of the light source to form a cured layer and adhere to the printing platform. Then the printing platform is lifted to complete the peeling of the cured layer and the release film, and then the printing platform is lowered to continue to form the next cured layer, and this process is repeated until the desired product model is completed. Due to the adhesion between the cured layer and the release film, it will increase the difficulty of peeling the cured layer and the release film, resulting in a decrease in printing efficiency. In order to improve printing efficiency, the material trough is usually swung or rotated to speed up the peeling of the cured layer and the release film.

[0004] Although the swinging method can speed up the peeling of the solidified layer and the release film, the photosensitive resin is easy to overflow the material tank in the tilted state. To avoid the overflow of the photosensitive resin, it is necessary to increase the depth of the material tank or reduce the liquid volume of the material tank. At the same time, due to the swinging, air is easy to mix in the photosensitive resin, affecting the printing quality of the product model.

[0005] Although the rotation method can also speed up the separation of the solidified layer and the release film, the separation process of the solidified layer and the release film can only rely on the lifting of the printing platform to complete the peeling of the solidified layer and the release film. When printing each product model, the printing platform needs to reciprocate at least dozens of times. Taking the commonly used solidified layer thickness of 0.05mm as an example, a product model with a height of 10mm needs to be printed at least 200 times. The frequent reciprocating motion of the printing platform is easy to cause wear to the ball screw and the screw nut, resulting in a decrease in printing accuracy and a reduction in the service life of the printing equipment.

[0006] Therefore, how to speed up the peeling speed of the curing layer and the release film, improve printing efficiency, reduce the wear of the ball screw, and extend the service life of the printing equipment while ensuring the quality of the product model is still a problem that needs to be solved in the development of top-pull light-curing 3D technology. Summary of the invention

[0007] In order to solve at least some of the above problems, the present application first proposes a release film peeling mechanism for a light-curing 3D printer, which includes a hollow shaft torque motor mounted on a top plate of a workbench; the hollow shaft torque motor is a servo motor;

[0008] The hollow shaft torque motor comprises a coaxially arranged mover, a stator and a hollow shaft, wherein the stator is rotatably sleeved on the outer periphery of the mover, the hollow shaft is fixedly lined on the inner wall of the mover, the central axis of the hollow shaft torque motor extends in the vertical direction, and the stator is fixed on a workbench; a lifting tube is threadedly engaged on the inner side of the hollow shaft, the lifting tube is limited to being able to reciprocate only in the vertical direction and cannot be rotated relative to the stator, and a liquid crystal screen is installed on the top of the lifting tube;

[0009] A limiting groove extending in the vertical direction is arranged on the outer peripheral surface of the lifting tube, and a limiting member is fixedly mounted on the stator, and the limiting member is inserted into the limiting groove;

[0010] A sleeve is fixed on the stator, and the sleeve is coaxially arranged with the hollow shaft. The material trough has a groove wall in an annular shape, and a release film is installed at the bottom of the groove wall. The groove wall of the material trough is threadedly engaged with the inner side of the sleeve. A guide hole extending in a vertical direction is arranged in the body of the groove wall. A guide rod is fixedly installed on the hollow shaft, and the guide rod is slidably inserted into the guide hole.

[0011] The trough has a first working position and a second working position, and the lifting tube has a third working position and a fourth working position. When the trough is located at the first working position, the lifting tube is located at the third working position; when the trough is located at the second working position, the lifting tube is located at the fourth working position; when the mover drives the hollow shaft to rotate, the trough can be reciprocated between the first working position and the second working position, and the lifting tube can be reciprocated between the third working position and the fourth working position at the same time;

[0012] When the material trough is located at the first working position and the lifting tube is located at the third working position, the light-curing 3D printer can perform printing work; when the material trough is located at the third working position and the lifting tube is located at the fourth working position, the release film and the product model on the printing platform are in a separated state.

[0013] In the present application, the trough and the LCD screen are both mounted on a hollow shaft torque motor, and when the mover rotates, the trough and the lifting tube are moved up and down synchronously, that is, the trough and the LCD screen can be moved up and down synchronously. When the 3D printer installed with the present application is working, it is necessary to first arrange the trough in the first working position and the lifting tube in the third working position, and then complete the printing of a solidified layer, and then rotate the mover, lower the trough to the second working position, and lower the lifting tube to the fourth working position, so that the solidified layer and the release film are separated, and then the trough is raised to the first working position and the lifting tube is raised to the third working position to print the next solidified layer. Since the trough is rotated while moving up and down, the peeling speed of the solidified layer and the release film can be increased. Since the trough moves down at the same time when the solidified layer and the release film are peeled off, the lifting height and moving speed of the printing platform can be reduced, thereby reducing the rotation speed of the ball screw, and since the printing platform is engaged on the ball screw through the screw nut, the wear of the ball screw and the screw nut can be reduced. Therefore, the present application can improve the peeling speed of the solidified layer and the release film while also improving the service life of the equipment.

[0014] In the present application, since part of the moving distance of the printing platform is shared by the movement of the material trough, the lowering height of the material trough and the LCD screen can be flexibly adjusted according to needs, so as to reasonably distribute the moving distance of the printing platform and the moving distance of the material trough and the LCD screen in the vertical direction, thereby minimizing the wear of the ball screw and the screw nut to the greatest extent and improving the service life of the equipment.

[0015] Furthermore, in order to avoid the restriction member from affecting the printing operation, one end of the restriction member is detachably fixed to the lower side of the stator, and the other end of the restriction member extends into the restriction groove. The restriction member is installed on the lower side of the stator so that the restriction member is located in the inner cavity of the workbench, which can effectively avoid the restriction member from affecting the printing operation.

[0016] Specifically, in order to make the material trough as close to the liquid crystal screen as possible, the upper surface of the liquid crystal screen should not be lower than the upper end surface of the lifting tube.

[0017] Furthermore, a light-transmitting glass is arranged at the bottom of the material trough, and a release film is laid on the light-transmitting glass; when the material trough is located at the first working position and the lifting tube is located at the third working position, the distance between the light-transmitting glass and the LCD screen is 0.2-1mm. This design can prevent the release film from being directly supported on the LCD screen. When the release film is directly supported on the LCD screen, the release film will rub against the LCD screen when the material trough rotates. After frequent friction, the light transmittance of the LCD screen will be reduced, thereby reducing the photocuring efficiency. Using light-transmitting glass to support the release film and spacing the light-transmitting glass and the LCD screen can effectively avoid mutual friction between the light-transmitting glass and the LCD screen when the material trough rotates, thereby reducing the light transmittance of both the light-transmitting glass and the LCD screen, thereby reducing the photocuring efficiency.

[0018] Furthermore, the printing platform has a central axis extending in the vertical direction, and in the horizontal direction, the central axis of the material trough is at a distance from the central axis of the printing platform. Preferably, the distance between the central axis of the material trough and the central axis of the printing platform is 5-15 mm. This design enables the bonding area of ​​the solidified layer and the release film to move relative to each other when the material trough rotates, so that the solidified layer and the release film can be peeled off smoothly. When the central axis of the material trough coincides with the central axis of the printing platform, when the material trough rotates, the area of ​​the release film located on the central axis will not move significantly with the solidified layer, and will also produce a vortex-like torsion with the central axis of the release film as the central axis, accelerating the failure of the release film.

[0019] Further, the pitch of the internal thread of the sleeve is the same as the pitch of the internal thread of the hollow shaft; or the pitch of the internal thread of the sleeve is smaller than the pitch of the internal thread of the hollow shaft. When the pitch of the internal thread of the sleeve is the same as the pitch of the internal thread of the hollow shaft, when the hollow shaft rotates, the lifting speed of the trough is the same as the lifting speed of the lifting tube, which can effectively prevent the collision between the LCD screen and the trough. When the pitch of the internal thread of the sleeve is smaller than the pitch of the internal thread of the hollow shaft, since the initial position of the trough is in the first working position and the initial position of the lifting tube is in the third working position during operation, the trough and the lifting tube are moved in the order of descending-ascending-descending-ascending, so the lifting speed of the lifting tube is greater than the lifting speed of the trough, and the LCD screen on the trough and the lifting tube will not collide with each other. However, in order to avoid the lifting tube from exceeding the third working position due to misoperation, causing the lifting tube to collide with the LCD screen, it is recommended to give priority to the solution in which the pitch of the internal thread of the sleeve is the same as the pitch of the internal thread of the hollow shaft. In order to make the material trough and the lifting tube move downward or upward synchronously, the spiral direction of the internal thread of the sleeve and the internal thread of the hollow shaft are opposite.

[0020] When the light-curing 3D printer equipped with any of the above items is in operation, the light-curing 3D printing method includes the following steps:

[0021] (1) Adjusting the positions of the material tank and the lifting tube so that the material tank is located at the first working position and the lifting tube is located at the third working position; immersing the printing platform into the photosensitive resin in the material tank so that there is a gap of the thickness of a solidified layer between the printing platform and the release film, and completing the printing of the first solidified layer;

[0022] (2) The printing platform is lifted upward, so that the rotor of the hollow shaft torque motor rotates forward, the material trough rotates downward to the second working position, and the lifting tube moves downward to the fourth working position synchronously, completing the peeling of the first solidified layer and the release film;

[0023] (3) The rotor of the hollow shaft torque motor is reversed, the material trough rotates upward to reach the first working position, and the lifting tube is synchronously moved upward to the third working position, and the printing platform is lowered so that there is a gap of the thickness of the first solidified layer and the release film, and the printing of the second solidified layer is completed;

[0024] (4) Repeat steps (2) and (3) to continue printing the solidified layer until the product model is printed.

[0025] In the present application, during the printing process of the product model, after each solidified layer is printed, the mover can be rotated, so that the material trough is lowered from the first working position to the second working position, and the lifting tube is lowered from the second working position to the fourth working position, and the material trough is rotated at the same time during the descent process, while accelerating the separation speed of the solidified layer and the release film. After the separation of the solidified layer and the release film is completed, the material trough is lifted upward while the printing platform is lowered. Since the reciprocating distance of the screw nut on the ball screw can be reduced, the wear between the screw nut and the ball screw can be reduced, thereby increasing the service life of the equipment.

[0026] Specifically, the number of revolutions of the trough is ≥ 0.2 revolutions. The number of revolutions of the trough does not need to exceed 1 revolution, and the number of revolutions of the trough can be controlled within 0.2-1 revolutions, and more preferably within 0.2-0.6 revolutions. When the trough rotates to a certain number of revolutions, the product model and the release film have been separated, and too many revolutions are not beneficial to the separation of the product model and the release film. When the trough rotates, the height of the trough's descent is controlled between 2-5mm, and the separation height of the product model and the release film is generally controlled between 5-10mm. The present application controls the descent height of the trough between 2-5mm, which is 20-50% of the separation height of the product model and the release film. This can reduce the reciprocating distance of the screw nut on the ball screw, thereby reducing the wear between the screw nut and the ball screw, and increasing the service life of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural diagram of an embodiment of the present application.

[0028] Figure 2 yes Figure 1 Center AA view.

[0029] Figure 3 yes Figure 1 Magnified view of part B.

[0030] Figure 4 yes Figure 1 Another state diagram of the accompanying drawing shown. DETAILED DESCRIPTION

[0031] The following first describes the light-curing 3D printer with a trough-sinking peeling method in this application. Figure 1-Figure 3 The light-curing 3D printer includes a workbench 10, which includes a vertical wall 11 in a rectangular cylindrical shape extending in a vertical direction, a bottom plate 12 installed at the bottom of the vertical wall, and a top plate 13 installed at the top of the vertical wall.

[0032] A transmission mechanism is installed on the workbench, and the transmission mechanism includes a column 15, a lifting motor 21, and a ball screw 22. The column 15 is fixedly installed on the top plate of the workbench, and the lifting motor 21 is installed at the bottom of the column. The ball screw extends in the vertical direction. One end of the lifting arm 16 is engaged with the ball screw through a screw nut, and the other end of the lifting arm extends in the horizontal direction away from the ball screw and forms a free end. The printing platform 17 is installed on the free end. Driven by the lifting motor, the lifting arm 16 can move up and down along the ball screw and drive the printing platform to move up and down. The lifting motor 21 specifically adopts a servo motor, and the specific transmission mechanism can be learned from the prior art.

[0033] The hollow shaft torque motor 70 is mounted on the top plate 13. The hollow shaft torque motor 70 includes a mover 75 and a stator 71 rotatably sleeved on the outside of the mover 75. A hollow shaft 76 is fixedly lined in the mover. An upper end cover 72 and a lower end cover 73 are respectively mounted on the upper and lower ends of the stator 71. The upper end cover 72 is bolted to an upper flange 711 at the upper end of the stator 71, and the lower end cover 73 is bolted to a lower flange 712 at the lower end of the stator 71. The upper flange 711 and the lower flange 712 are integrally formed on the stator 71. The stator 71, the mover 75 and the hollow shaft 76 are coaxially arranged.

[0034] In this embodiment, an upper connecting flange 761 is provided on the upper part of the outer circumferential surface of the hollow shaft 76, and the upper end cover has an upper abutting flange 721 protruding inwardly, and the lower surface of the upper abutting flange 721 is a step surface facing downward. The upper abutting flange 721 is pressed against the upper side of the outer ring of the upper angular contact bearing 771 through its lower surface, and the upper connecting flange 761 is pressed against the lower side of the inner ring of the upper angular contact bearing, so that the upper end cover is rotatably connected to the hollow shaft 76 through the upper angular contact bearing.

[0035] A lower step portion 762 is provided at the lower part of the outer circumference of the hollow shaft 76, and the lower step portion has a step surface facing downward, and the lower step portion 762 is formed by the outer circumference of the hollow shaft 76 being recessed radially inward; the lower end cover has a lower abutting flange 731 protruding inward, and the upper surface of the lower abutting flange 731 is a step surface facing upward, and the lower abutting flange 731 abuts against the lower side of the outer ring of the lower angular contact bearing 772 through its upper surface, and the lower step portion 762 presses against the upper side of the inner ring of the lower angular contact bearing, so that the lower end cover is rotatably connected to the hollow shaft 76 through the lower angular contact bearing. A winding 74 is provided on the inner side of the stator. The structure of the hollow shaft torque motor can be completed by using existing mature technology, and no further description is given.

[0036] In this embodiment, in order to reduce the influence of the hollow shaft torque motor 70 on the printing work, a step hole 19 is opened on the top plate, and the step hole 19 is larger at the top and smaller at the bottom, so that the step hole has a step surface 191 facing upward. A stator flange 713 is provided on the outer peripheral surface of the stator 71, and the stator flange is supported on the step surface 191. The fixing bolts 714 connect the stator flange to the top plate 13, so that the hollow shaft torque motor 70 is installed on the top plate.

[0037] A first internal thread is provided on the inner circumferential surface of the hollow shaft 76, and a first external thread is provided on the outer wall of the lifting tube 41. The lifting tube 41 is engaged with the first internal thread of the hollow shaft 76 via the first external thread, so that the lifting tube 41 is threadedly engaged on the inner side of the hollow shaft 76. The lifting tube 41 is limited to be able to reciprocate only in the vertical direction and cannot rotate relative to the stator.

[0038] In this embodiment, a limiting groove 43 extending in the vertical direction is provided on the outer circumferential surface of the lifting tube, and a limiting member 69 is fixedly installed on the lower side of the lower end cover by bolts, and the limiting member is inserted into the limiting groove 43. The limiting member 69 is specifically a steel plate, and one end of the limiting member 69 is detachably fixed to the lower surface of the lower end cover by bolts, and the other end of the limiting member 69 extends into the limiting groove after passing over the mover. When the mover drives the hollow shaft to rotate, due to the limiting effect of the limiting member 69, the lifting tube can only reciprocate in the vertical direction, and cannot rotate relative to the hollow shaft.

[0039] In order to prevent the lifting tube 41 from falling off the hollow shaft 76 downward, a limiting flange 42 is provided at the top of the lifting tube 41. The limiting flange 42 is formed by the outer peripheral surface of the lifting tube protruding radially outward, and the limiting flange 42 can be supported on the top of the hollow shaft, thereby preventing the lifting tube from falling off the hollow shaft 76 downward.

[0040] The LCD screen 18 is mounted on the top of the lifting tube. In this embodiment, the upper surface of the LCD screen is flush with the upper end surface of the lifting tube. It can be understood that in other embodiments, the upper surface of the LCD screen can also exceed the upper end surface of the lifting tube. However, the height of the upper surface of the LCD screen exceeding the upper end surface of the lifting tube should not be too large, generally not exceeding 1mm. To facilitate the installation of the LCD screen 18, a support ring 44 is provided on the inner wall of the lifting tube, and the LCD screen is supported on the support ring.

[0041] The sleeve 36 is fixedly mounted on the upper end cover 72. A sleeve flange 34 extending radially outward is provided at the lower end of the sleeve. A sleeve bolt 35 passes through the sleeve flange 34 and is screwed onto the upper end cover 72, so that the sleeve 36 is indirectly fixed to the stator via the upper end cover.

[0042] The sleeve is coaxially arranged with the hollow shaft, and the inner wall of the sleeve has a second internal thread. The material tank 30 has a ring-shaped tank wall 31, a light-transmitting glass 33 is installed at the bottom of the tank wall, and a release film is laid on the upper surface of the light-transmitting glass. A second external thread is arranged on the outer peripheral surface of the tank wall, and the material tank is screwed on the second internal thread through the second external thread, so that the tank wall thread is engaged with the inner side of the sleeve.

[0043] A guide hole 32 extending in the vertical direction is provided in the body of the trough wall, and a guide rod 37 is fixedly installed on the hollow shaft, and the guide rod is slidably inserted into the guide hole. In this embodiment, when installing the trough, the trough needs to be screwed into the sleeve first, and after the distance between the trough and the mover reaches the set distance, the guide rod is inserted into the guide hole, and the guide rod is screwed into the bolt hole at the top of the hollow shaft. The set distance is determined according to the height to which the trough needs to be lowered.

[0044] The trough has a first working position and a second working position, and the lifting tube has a third working position and a fourth working position. When the trough is located at the first working position, the lifting tube is located at the third working position; when the trough is located at the second working position, the lifting tube is located at the fourth working position. When the mover drives the hollow shaft to rotate, the trough can reciprocate between the first working position and the second working position, and at the same time, the lifting tube can reciprocate between the third working position and the fourth working position.

[0045] Please also see Figure 1 and Figure 4 , Figure 1 In the process, the trough is in the first working position, and the lifting tube is in the third working position. Figure 4In the embodiment, the material trough is in the second working position, and the lifting tube is in the fourth working position. When the material trough is in the first working position and the lifting tube is in the third working position, the printing platform can be immersed in the photosensitive resin in the material trough to perform printing. When the material trough is in the third working position and the lifting tube is in the fourth working position, the product model on the printing platform and the release film of the release film are in a separated state. When the mover drives the hollow shaft to rotate, the material trough can be rotated downward from the first working position to the second working position, and the lifting tube can be synchronously moved downward from the third working position to the fourth working position, or the material trough can be rotated upward from the second working position to the first working position, and the lifting tube can be synchronously moved upward from the fourth working position to the third working position.

[0046] In order to avoid friction between the light-transmitting glass and the liquid crystal screen when the material trough is rotating, which causes wear on both, in this embodiment, when the material trough is in the first working position and the lifting tube is in the third working position, there is a gap of 0.5mm between the light-transmitting glass and the liquid crystal screen. The distance between the light-transmitting glass and the liquid crystal screen should not be too large, preferably 0.2-1mm, and can also be 0.2mm, 0.4mm, 0.8mm or 1mm, and of course other distances between 0.2-1mm. An ultraviolet light system 14 is installed in the inner cavity of the workbench, and the ultraviolet light emitted by the ultraviolet light system can irradiate the liquid crystal screen. In this embodiment, the ultraviolet light system adopts existing mature technology and will not be described in detail.

[0047] In order to reduce the interference of the guide rod on the work, in this embodiment, when the trough is in the first working position and the lifting tube is in the third working position, the top of the guide rod is lower than the top of the trough wall of the trough. The guide rod in this embodiment is a cylindrical rod. In order to facilitate the screwing of the guide rod, a regular hexagonal screw hole is provided on the top of the guide rod. The hexagonal wrench can be inserted into the screw hole to screw the guide rod into the threaded hole at the top of the hollow shaft, or to screw the guide rod out of the threaded hole.

[0048] The printing platform has a second central axis 171 extending in the vertical direction. Since the sleeve is coaxially arranged with the hollow shaft, the material trough is screwed on the sleeve, so that the material trough is coaxially arranged with the hollow shaft, that is, the material trough is coaxially arranged with the hollow shaft torque motor, and the first central axis 311 of the hollow shaft torque motor 70 is also the central axis of the material trough. In the horizontal direction, there is a distance H between the first central axis and the second central axis. In this embodiment, the distance H between the first central axis and the second central axis in the horizontal direction is 5mm. The distance H between the first central axis and the second central axis in the horizontal direction is preferably 5-15mm. In other embodiments, the distance H can be selected according to the size of the material trough. The larger the material trough, the larger the distance H between the first central axis and the second central axis in the horizontal direction, but there is no special requirement in the specific selection. Figure 2 In the figure, for clarity, the second central axis 171 and the first central axis 311 are both represented by a small circle, and Figure 2 In the figure, the position of the printing platform in the trough is indicated by a dotted line.

[0049] The purpose of setting the first central axis and the second central axis at intervals is to extend the service life of the release film. When the first central axis and the second central axis overlap, when the trough rotates, the point on the first central axis is actually in a stationary state. Driven by the product model, the release film will produce a vortex-like twist with the first central axis as the central axis, accelerating the failure of the release film. After the first central axis and the second central axis are set at intervals, when the trough rotates, the product model can move as a whole with the release film, avoiding the above-mentioned vortex-like twist, which is more conducive to the separation of the product model and the release film, and ensuring the service life of the release film.

[0050] In this embodiment, the pitch of the second internal thread of the sleeve is the same as the pitch of the first internal thread of the hollow shaft, so that when the hollow shaft rotates, the lifting speed of the trough is the same as the lifting speed of the lifting tube. It can be understood that in another embodiment, the pitch of the second internal thread of the sleeve can also be smaller than the pitch of the first internal thread of the hollow shaft. At this time, the lifting speed of the trough is smaller than the lifting speed of the lifting tube. Since the initial position of the trough is in the first working position and the lifting tube is in the third working position during operation, the trough and the lifting tube move in the order of descending-ascending-descending-ascending. Therefore, the trough and the LCD screen on the lifting tube will not collide with each other due to the lifting speed of the lifting tube being greater than the lifting speed of the trough. However, in order to avoid the lifting tube from exceeding the third working position upward due to misoperation, causing the collision between the trough and the LCD screen, it is recommended to preferentially adopt the solution that the pitch of the second internal thread of the sleeve is the same as the pitch of the first internal thread of the hollow shaft. In order to make the trough and the lifting tube move downward or upward synchronously, the spiral direction of the second internal thread of the sleeve is opposite to that of the first internal thread of the hollow shaft.

[0051] The following is an explanation of the light-curing 3D printing method in the present application. The light-curing 3D printing method is performed using the above-mentioned trough-sinking peeling light-curing 3D printer. The light-curing 3D printing method includes the following steps:

[0052] (1) Adjusting the positions of the material tank and the lifting tube so that the material tank is located at the first working position and the lifting tube is located at the third working position; immersing the printing platform into the photosensitive resin in the material tank so that there is a gap of the thickness of a solidified layer between the printing platform and the release film, and completing the printing of the first solidified layer;

[0053] (2) The printing platform is lifted upward, so that the rotor of the hollow shaft torque motor rotates forward, the material trough rotates downward to the second working position, and the lifting tube moves downward to the fourth working position synchronously, completing the peeling of the first solidified layer and the release film;

[0054] (3) The rotor of the hollow shaft torque motor is reversed, the material trough rotates upward to reach the first working position, and the lifting tube is synchronously moved upward to the third working position, and the printing platform is lowered so that there is a gap of the thickness of the first solidified layer and the release film, and the printing of the second solidified layer is completed;

[0055] (4) Repeat steps (2) and (3) to continue printing the solidified layer until the product model is printed.

[0056] To maximize the printing efficiency, when the printing platform is lifted upward, the hollow shaft torque motor is started synchronously to make its mover rotate forward. When the mover is reversed, the printing platform is lowered synchronously. In this embodiment, during the process of peeling the solidified layer from the release film, the number of turns of the material trough is 0.4 turns.

Claims

1. A release film peeling mechanism for a light-curing 3D printer, characterized in that: It includes a hollow shaft torque motor mounted on the top plate of the workbench; the hollow shaft torque motor is a servo motor; The hollow shaft torque motor comprises a coaxially arranged mover, a stator and a hollow shaft, wherein the stator is rotatably sleeved on the outer periphery of the mover, the hollow shaft is fixedly lined on the inner wall of the mover, the central axis of the hollow shaft torque motor extends in the vertical direction, and the stator is fixed on a workbench; a lifting tube is threadedly engaged on the inner side of the hollow shaft, the lifting tube is limited to being able to reciprocate only in the vertical direction and cannot be rotated relative to the stator, and a liquid crystal screen is installed on the top of the lifting tube; A limiting groove extending in the vertical direction is arranged on the outer peripheral surface of the lifting tube, and a limiting member is fixedly mounted on the stator, and the limiting member is inserted into the limiting groove; A sleeve is fixed on the stator, and the sleeve is coaxially arranged with the hollow shaft. The material trough has a groove wall in an annular shape, and a release film is installed at the bottom of the groove wall. The groove wall of the material trough is threadedly engaged with the inner side of the sleeve. A guide hole extending in a vertical direction is arranged in the body of the groove wall. A guide rod is fixedly installed on the hollow shaft, and the guide rod is slidably inserted into the guide hole. The trough has a first working position and a second working position, and the lifting tube has a third working position and a fourth working position. When the trough is located at the first working position, the lifting tube is located at the third working position; when the trough is located at the second working position, the lifting tube is located at the fourth working position; when the mover drives the hollow shaft to rotate, the trough can be reciprocated between the first working position and the second working position, and the lifting tube can be reciprocated between the third working position and the fourth working position at the same time; When the material trough is located at the first working position and the lifting tube is located at the third working position, the light-curing 3D printer can perform printing work; When the material trough is located at the third working position and the lifting tube is located at the fourth working position, the release film and the product model on the printing platform are in a separated state.

2. The release film peeling mechanism according to claim 1, characterized in that: One end of the limiting member is detachably fixed to the lower side of the stator, and the other end of the limiting member extends into the limiting groove.

3. The release film peeling mechanism according to claim 1, characterized in that: The upper surface of the liquid crystal screen is not lower than the upper end surface of the lifting tube.

4. The release film peeling mechanism according to claim 1, characterized in that: A light-transmitting glass is arranged at the bottom of the material trough, and a release film is laid on the light-transmitting glass; when the material trough is located at the first working position and the lifting tube is located at the third working position, the distance between the light-transmitting glass and the LCD screen is 0.2-1mm.

5. The release film peeling mechanism according to claim 1, characterized in that: The printing platform has a central axis extending in a vertical direction. In a horizontal direction, there is a distance between the central axis of the material trough and the central axis of the printing platform.

6. The release film peeling mechanism according to claim 1, characterized in that: The pitch of the internal thread of the casing is the same as the pitch of the internal thread of the hollow shaft; or the pitch of the internal thread of the casing is smaller than the pitch of the internal thread of the hollow shaft.

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